> up to 8.7GW (and probably never less than 1GW).

And then we would also would have had to build ~8GW of new gas/oil/coal plants or dam more rivers for hydro.

Electricity is used for heating in Finland. Not having enough electricity in the winter is not an option. We need ~9GW of constant production with peaking to around 13GW to survive winters.

edit: Or some absolutely insane amounts of storage to store a week or two of that ~8GW to handle the worst case scenarios.